The present invention relates to a mold core and the method by which it is used to form internal passages in a cast article, such as an airfoil.
Cores have been used to form passages in airfoils in a manner generally similar to that disclosed in U.S. Pat. Nos. 2,362,745; 3,401,738; 3,659,645; 3,596,703 and 3,662,816. The cores are positioned relative to airfoil mold cavities by pin members. These pin members extend from the molds into engagement with the cores.
Cores of a ceramic material have been formed with a relatively long length and small transverse cross sectional area. These cores are easily broken during handling in a foundry. In addition, there is a tendency for sections of a core to shift relative to each other during forming of a pattern and mold and during casting of an airfoil.